When capturing image data using an image sensor or other image capture device, such as a camera, it is common to include a flash, strobe, or other component that uses an illumination element, such as a light emitting diode (LED), that emits light to illuminate portions of a scene located within a field of view of the image sensor. As image sensors are often embedded in a wide variety of devices, different types of flash components may be implemented to suit the constraints or design requirements of the different devices that include the image sensors. For example, mobile computing devices, such as mobile phones or other portable multi-function devices, may implement image sensors and flash components that occupy a limited portion of the mobile computing device, leaving space for other elements or components of the mobile computing device to provide other functions or capabilities. Therefore, techniques to reduce the space or resources occupied by flash components or image sensors may be desirable.
In various embodiments, a Fresnel lens may be implemented to illuminate a scene or other portion within the field of view of an image sensor, directing light received from an illumination element or other light source into the field of view. The Fresnel lens may include multiple different zones for directing received light. While one or more of the zones in the Fresnel lens may be radially symmetric, another one or more of the zones may be asymmetric, resulting in a zone that is radially asymmetric. The asymmetric zone may provide localized redirection of light so that different portions of the asymmetric zone direct light differently. One embodiment of an asymmetric zone may, for instance, redirect light to provide inverted illumination in the field of view, while another embodiment of an asymmetric zone may redirect light to provide a non-inverted illumination in the field of view. Different combinations of multiple asymmetric zones may be implemented within a single Fresnel lens or multiple Fresnel lenses implemented together as part of a same light source module.
This specification includes references to “one embodiment” or “an embodiment.” The appearances of the phrases “in one embodiment” or “in an embodiment” do not necessarily refer to the same embodiment. Particular features, structures, or characteristics may be combined in any suitable manner consistent with this disclosure.
“Comprising.” This term is open-ended. As used in the appended claims, this term does not foreclose additional structure or steps. Consider a claim that recites: “An apparatus comprising one or more processor units . . . ” Such a claim does not foreclose the apparatus from including additional components (e.g., a network interface unit, graphics circuitry, etc.).
“Configured To.” Various units, circuits, or other components may be described or claimed as “configured to” perform a task or tasks. In such contexts, “configured to” is used to connote structure by indicating that the units/circuits/components include structure (e.g., circuitry) that performs those task or tasks during operation. As such, the unit/circuit/component can be said to be configured to perform the task even when the specified unit/circuit/component is not currently operational (e.g., is not on). The units/circuits/components used with the “configured to” language include hardware—for example, circuits, memory storing program instructions executable to implement the operation, etc. Reciting that a unit/circuit/component is “configured to” perform one or more tasks is expressly intended not to invoke 35 U.S.C. § 112(f) for that unit/circuit/component. Additionally, “configured to” can include generic structure (e.g., generic circuitry) that is manipulated by software and/or firmware (e.g., an FPGA or a general-purpose processor executing software) to operate in manner that is capable of performing the task(s) at issue. “Configure to” may also include adapting a manufacturing process (e.g., a semiconductor fabrication facility) to fabricate devices (e.g., integrated circuits) that are adapted to implement or perform one or more tasks.
“First,” “Second,” etc. As used herein, these terms are used as labels for nouns that they precede, and do not imply any type of ordering (e.g., spatial, temporal, logical, etc.). For example, a buffer circuit may be described herein as performing write operations for “first” and “second” values. The terms “first” and “second” do not necessarily imply that the first value must be written before the second value.
“Based On.” As used herein, this term is used to describe one or more factors that affect a determination. This term does not foreclose additional factors that may affect a determination. That is, a determination may be solely based on those factors or based, at least in part, on those factors. Consider the phrase “determine A based on B.” While in this case, B is a factor that affects the determination of A, such a phrase does not foreclose the determination of A from also being based on C. In other instances, A may be determined based solely on B.